In recent years, in accordance with, for example, a demand for reducing travel cost and time, a communication system which provides calling and conferencing over a communication network such as the Internet or a dedicated line or the like has become popular.
In this kind of communication system, when a communication between communication terminals is started, content data such as image data and audio data are sent and received (see PTL 1).
When using a communication system at a call center, a method is known in which, in response to a connection request from a video phone, a call center apparatus selects a currently available operator terminal to receive a call, and establishes a communication channel for video and audio between the selected operator terminal and the video phone (see PTL 2). This makes it possible for an operator terminal that is in a state in which an incoming call can be received after having terminated communication with a video phone, to start communication with another video phone.